Adapting white LEDs as festoon bulbs?

Where 5mm is the maximum dimension / available space of the original bulb so you cannot turn aroud the LED. Would be useful for replacing awkward voltage festoon bulbs. The maximum beam of 5mm LEDs is axially but how to convert to transverse? Grind an angle to the dome and melt on some mylar? Wrap whole LED in mylar except for an axial slot? Abraid the LED all round to make translucent rather than clear?

Then adapting AC or DC supply to suit

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook
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Are you restricted to 5mm types? There are also very short ones available.

Problem with LEDs is the diabolical 'colour' if used as a replacement for tungsten. Which may not matter, of course.

--
*I'm pretty sure that sex is better than logic, but I can't prove it.  

    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

You can buy 12v led festoon bulbs, Google for led car accessories.

Ron

Reply to
Ron(UK)

**Nonsense. LEDs are available in a wide variety of shapes and sizes. Many are much smaller than 5mm.
**Again, wrong. Lumiled (and others) manufacture LEDs with a 120o (or more) light spread.
**Try not to re-invent the wheel. Look at the alternatives. They are easy enough to find.

Trevor Wilson

Reply to
Trevor Wilson

While I've built LED replacements in a pinch, this is one of those things where it makes more sense to buy a ready made LED retrofit lamp than to try to build something, unless maybe you already have a bunch of LEDs you want to put to use.

Reply to
James Sweet

bulb

transverse?

try

I have 27 salvaged 35mA ,5mm white o/p LEDs and no 3mm, and every now and then need a festoon bulb that is usually not 12V.

The bluishness can be compensated for to a certain extent by coating with varnish with a tiny spot of red dye mixed in.

So far the best conversion seems to be 1.25 inch fuse glass barrel with ends removed, scored and cut down to size , heated and pushed over an LED and an oval of muylar glued into the open end, forming a 45 degree or so mirror. Placing back the fuse ends for soldering to, with wires taken external to the barrel.. Then a wash of vaguely red tinted varnish over the glass.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

so

voltage

Question...what the heck is a "festoon", and why does it need bulbs? Are we talking outdoor lighting?

Reply to
Deke

Double ended tubular bulbs, I think it's primarily British terminology. Many automotive dome lights use them.

Reply to
James Sweet

OH. Ok.. The dictonary wasn't helping because the defition for festoon is either festive deocoration or feast.

Reply to
Michael Kennedy

Are

So what is the USA name for filament bulbs that look like 1.25 inch or 20mm fuses, so I can add to my "translator" file

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-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

The ones I've seen are of a larger diameter than a 6 watt festoon type.

10mm seems to be the common diameter - so a replacement for 10/18w types. I suspect by the text it's the smaller one Mr Cook wants to replace - meter lights etc?
--
*Funny, I don't remember being absent minded.

    Dave Plowman        dave@davenoise.co.uk           London SW
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Dave Plowman (News)

Or you could spend £1.99 and buy one with three white leds ready made.

Reply to
Ron(UK)

Domelight

Ron

Reply to
Ron(UK)

With the larger ones there is no great problem finding some sort of filament bulb to replace it with. But small diameter , high wattage ones, like the those built into meters are a different matter.

3mm LEDs, in there, would give a spot light which would not be distributed by the white plastic housing, giving a very poor meter illumination

I've never tried melting an LED before , not that easy.

In the process I found that filling the glass barrel with translucent hot melt glue gives quite a good linear diffused illumination. Air entrained clear glue or plastic would probably be a bit better but hot-melt is quite convenient.

Domelamp =USA= barrel filament bulb, or the automotive housing where they are found ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

The point of a festoon bulb, or the wire-ended ones, is you can put in a lot of wattage, get out a lot of illumination, by using a package that is quite large in one dimension, only, unlike having to expand all 3 dimensions of a globe bulb.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

Comparison of 2 in series

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as original LED and then a half length, 1 1/4 inch fuse barrel filled with hot-melt glue.

A bit more scientifically measuring the original transverse, at a given distance over matt black carbon/foam , was about 30 lux, modified LED about

180 lux and for comparison a 12V 6W festoon lamp at the same distance about 1000 lux.

Comparison of illumination , by readable text, at a distance of a foot I would say the modified LED was equivalent to the 12V bulb running at 0.1 amps rather than 0.2A. So at least 2 such LEDs at 30mA to have any chance of equalling the illumination of the festoon. So a white LED at each end of a filled glass barrel , at least , needed to equal.

The mylar mirror just gave 2 bright spots rather than an illuminator, but "frosting" of the glass may still work

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

Cartridge Lamp

Michael

Reply to
msg

I used to have the paints for coating lamps or glass from craft stores. I'll have to try your mixture for led's. Warm white led's are becomming more common, and are required for illumination of different things in the home. My current need is making under cabinet kitchen lamps.

greg

Reply to
GregS

Not according to Goofle/images "Cartridge Lamp"

79 hits , only 1 in first 2 pages that I would call a festoon bulb

put "festoon bulb", 477 hits in google/images and first page is nearly full of them

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

There`s plenty if you Google for Dome Light bulb I bet

I`ve always thought of a festoon lamp as having metal endcaps, we used them a lot on slot machines back in the 60`s. I`ve never thought of wire ended miniature tubular lamps as festoons.

There was at one time available a flexible strip containing lots of back to back clips (like open fuseholders) specifically for making up "festoons" of lighting - I`m going back to the days of the old RadioSpares catalogue here. I always imagined that`s where the name festoon lamp came from.

Ron(UK)

Reply to
Ron(UK)

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